Measurement got cheaper. Your agency contract didn't notice.
Independent media measurement used to be an enterprise purchase. It now costs about half as much and takes weeks, yet most agency contracts still pay for delivery.
For most of the last decade, a marketing mix model was an enterprise purchase. Six figures, six months, and a deck that was out of date by the time the board saw it. Mid-market brands relied on platform reporting, which grades its own homework, and on the agency's view of what worked.
We've been the agency presenting that view. It was rarely dishonest. It was rarely independent either.
What changed
| Then | Now | |
|---|---|---|
| Mix model cost | At least $250,000 per study | Roughly half that |
| Turnaround | About six months | As little as four to six weeks |
| Software | Proprietary, vendor-held | Open source options, including Google's Meridian |
| Trust | Platform reporting by default | Incrementality tests trusted most |
Google made its open-source Meridian model available to everyone in January 2025, with more than 20 certified measurement partners. Digiday reported in July 2026 that a mix model study that took six months and at least $250,000 can now cost roughly half and take as little as four to six weeks. Incrementality testing has gone mainstream too. In a January 2026 survey of 500 US senior decision-makers by Haus, which sells incrementality testing, reported by EMARKETER, 60% said they trust incrementality testing most, against 40% for mix models and 37% for in-platform reporting.
Yet only 39% of teams use mix modeling, attribution and incrementality together, according to the IAB's State of Data 2026, mostly because integrating them is slow and complex. And most agency contracts still define success as delivery: impressions, reach, cost per click.
Why it matters for 2027
When independent measurement was expensive, letting the agency mark its own work was a reasonable compromise. It isn't any more. If you can learn which channels drive sales in six weeks for roughly half the old price, a contract that pays for delivery rather than outcomes is a choice.
The first thing we check in a media audit is who produces the performance read. If it's the same team that buys the media, the incentives point one way, however good the people are.
Three moves for the 2027 plan
Fund one independent read. A mix model or a structured set of incrementality tests, owned by you and not run by the agency that buys the media. Our rule of thumb for a first study: pick the two or three channels that take most of the budget and test those, rather than modeling everything at once.
Write it into the contract. Agency KPIs tied to the measured outcome, reviewed once a year. The agency contributes data and plans against the result. It doesn't grade it.
Own the data. Log-level files and platform seats in your name. You can't measure what you can't see, and you can't switch measurement partners if the agency holds the inputs.
The likely pushback
Expect three objections. The model is only as good as the data (true, which is why you own the data). Incrementality tests cost reach while they run (also true, so size the holdout sensibly). The agency already has a measurement product (fine, it can be one input, not the referee).
The brands that do this will spend 2027 moving budget to what works. The rest will spend it debating whose numbers are right.
Sources: Google, Meridian is now available to everyone, January 2025, Digiday, Future of Marketing Briefing, July 2026, EMARKETER, Incrementality testing earns marketers' top trust, 2026, MediaPost, IAB State of Data 2026.
Is marketing mix modeling affordable for a mid-market brand?
Increasingly, yes. Digiday reported in July 2026 that a study that once took six months and at least $250,000 can now cost roughly half and take four to six weeks, helped by open-source models such as Google's Meridian.
Should the agency run our measurement?
The agency should contribute data, but the read on what works should be owned by the brand and independent of the team that buys the media.
What should agency KPIs be tied to?
Measured business outcomes from a mix model or incrementality tests, reviewed once a year, rather than delivery metrics such as impressions or cost per click.
Finding value a business did not know it had is the part of this work we enjoy most. If you are not sure which half of your media is working, fifteen minutes is enough to tell you how we would find out.